I'm a partner in a 77 Lance (300hp). There are three of us that own it together. Basically the same plane, except ours retracts. We burn 13.5 at cruise. File for 145kts. It has been better than I expected. I can load my two teenage boys, the wife and myself in with luggage / fuel and fly from SC to the Bahamas nonstop in 3.5 hrs for spring breaks. What's not to like?
Having the partners to split costs has been great. You must have an agreement and be comfortable in how the partnership works. Must clearly know cost to get in, how exit works, how costs are shared and how time is split. We have been very happy.